Keep never in MutatingScope::intersectButNotNever() instead of widening it to null

src/Analyser/MutatingScope.php

@@ -2621,6 +2621,12 @@ public static function intersectButNotNever(Type $nativeType, Type $inferredType
 		}
 
 		$result = TypeCombinator::intersect($nativeType, $inferredType);
+		if ($result instanceof NeverType) {
+			// the inferred type says no value is ever produced - the native
+			// type's nullability must not resurrect one
+			return $result;
+		}
+
 		if (TypeCombinator::containsNull($nativeType)) {
 			return TypeCombinator::addNull($result);
 		}

tests/PHPStan/Analyser/nsrt/bug-15285.php

@@ -0,0 +1,99 @@
+<?php // lint >= 8.2
+
+declare(strict_types = 1);
+
+namespace Bug15285;
+
+use Closure;
+use Generator;
+use LogicException;
+use RuntimeException;
+use function PHPStan\Testing\assertType;
+
+final class CartController
+{
+
+	public function redirect(string $destination): never
+	{
+		throw new RuntimeException($destination);
+	}
+
+	/**
+	 * @param Closure(string, (Closure(): never)|null=): never $errorCallback
+	 */
+	public function addToCart(bool $isAvailable, Closure $errorCallback): void
+	{
+		if ($isAvailable) {
+			return;
+		}
+
+		$errorCallback(
+			'This offer is no longer available.',
+			fn (): null => $this->redirect('/product'),
+		);
+	}
+
+	public function dump(): void
+	{
+		assertType('Closure(): never', fn () => $this->redirect('/product'));
+		assertType('Closure(): never', fn (): null => $this->redirect('/product'));
+		assertType('Closure(): never', fn (): int => throw new LogicException());
+		assertType('Closure(): never', fn (): ?int => throw new LogicException());
+
+		assertType('Closure(): never', function () {
+			$this->redirect('/product');
+		});
+		assertType('Closure(): never', function (): null {
+			$this->redirect('/product');
+		});
+		assertType('Closure(): never', function (): ?int {
+			throw new LogicException();
+		});
+
+		assertType('static-Closure(): never', static fn (): ?int => throw new LogicException());
+		assertType('static-Closure(): never', static function (): null {
+			throw new LogicException();
+		});
+
+		assertType('Closure(): never', function (): ?Generator {
+			throw new LogicException();
+		});
+		assertType('Closure(): Generator<int, 1, mixed, void>', function (): ?Generator {
+			yield 1;
+		});
+	}
+
+}
+
+/**
+ * @param list<never> $emptyList
+ */
+function neverCallableParameters(array $emptyList): void
+{
+	array_map(function (?int $i): void {
+		assertType('never', $i);
+	}, $emptyList);
+
+	array_map(fn (?int $i) => assertType('never', $i), $emptyList);
+
+	array_map(function (null $i): void {
+		assertType('never', $i);
+	}, $emptyList);
+}
+
+/**
+ * @param callable(never...): void $cb
+ */
+function neverVariadicCallable(callable $cb): void
+{
+}
+
+function neverVariadicCallableParameters(): void
+{
+	neverVariadicCallable(function (?int $a, ?string $b): void {
+		assertType('never', $a);
+		assertType('never', $b);
+	});
+
+	neverVariadicCallable(fn (?int $a) => assertType('never', $a));
+}

tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php

@@ -449,6 +449,12 @@ public function testBug15251(): void
 		$this->analyse([__DIR__ . '/../Methods/data/bug-15251.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.2.0')]
+	public function testBug15285(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-15285.php'], []);
+	}
+
 	#[RequiresPhp('>= 8.0.0')]
 	public function testBug11935WithCheckExplicitMixed(): void
 	{

tests/PHPStan/Rules/Functions/data/bug-15285.php

@@ -0,0 +1,33 @@
+<?php // lint >= 8.2
+
+declare(strict_types = 1);
+
+namespace Bug15285CallCallables;
+
+use Closure;
+use RuntimeException;
+
+final class CartController
+{
+
+	public function redirect(string $destination): never
+	{
+		throw new RuntimeException($destination);
+	}
+
+	/**
+	 * @param Closure(string, (Closure(): never)|null=): never $errorCallback
+	 */
+	public function addToCart(bool $isAvailable, Closure $errorCallback): void
+	{
+		if ($isAvailable) {
+			return;
+		}
+
+		$errorCallback(
+			'This offer is no longer available.',
+			fn (): null => $this->redirect('/product'),
+		);
+	}
+
+}